Wet vents or missing vents?

I hired a plumber to inspect a new construction house that I'm buying. His report says that many of the plumbing fixtures do not have vents. I'm wondering if it might be possible that the house is wet vented?

I'm trying to get in touch with him but he's out on a job… hopefully he will call me back soon. In the meantime, I am curious to hear opinions on this matter. I can't imagine he would have not noticed if the house is wet vented, but I also can't imagine that the builder omitted vents.

Here is what the report said:

-- Master bath stool and shower not vented. There is only 1.5" vent coming into the attic for the master bath.

-- 2nd bathroom. Stool and shower/tub not vented. We believe the sink is vented, but can't see with the blown insulation. It also appears to have only an 1.5" vent coming into the attic.

-- Laundry has no vents for laundry sink or washer drain visible in attic.

-- The only fixtures that appear to be vented are the kitchen sink, master sink, and possibly the second bathroom.

If this is new construction, there should be a signed plumbing permit on the job.
Then I would ask that plumbing inspector.

UPC does allow for some wet venting, and also the use of AAV vents.
For a three bath home, you would still need either a single 3" vent through the roof, or two 2" vents and a 1.5" vent, which make up a 3"
We require 2" for a bathroom set vent.

I sent the plumbing inspection report to the builder. The builder didn't say anything specific about the report, but he did say that the plumbing meets code. He said that the building inspector checked out the plumbing after it was roughed in and again after it was finished before it was closed in with drywall. The building inspector said it was good to go.

After I got this response from the builder, I spoke with the plumber who did the inspection and told him what the builder said. The plumber said there was one more thing that he noticed about the plumbing that wasn't in his report -- he said that he couldn't find a 3" vent stack in the crawlspace. The only vents coming up from the crawlspace (that he could find) are 1.5" vents. Could that meet code? Or maybe there is a 3" vent stack but he couldn't find it? He did say that he found a 3" vent in the attic that goes through the roof, and all of the 1.5" pipes he found were tied into this main vent that exhausts through the roof.

The other thing I'm wondering is whether or not a laundry room needs to be vented. It has a washer, dryer, and sink. The plumber could only find 1.5" vents coming up from the two bathrooms and the kitchen sink, but nothing coming from the laundry room. Maybe the vent is hidden in the walls and attic insulation.

I sent the plumbing inspection report to the builder. The builder didn't say anything specific about the report, but he did say that the plumbing meets code. He said that the building inspector checked out the plumbing after it was roughed in and again after it was finished before it was closed in with drywall. The building inspector said it was good to go.

After I got this response from the builder, I spoke with the plumber who did the inspection and told him what the builder said. The plumber said there was one more thing that he noticed about the plumbing that wasn't in his report -- he said that he couldn't find a 3" vent stack in the crawlspace. The only vents coming up from the crawlspace (that he could find) are 1.5" vents. Could that meet code? Or maybe there is a 3" vent stack but he couldn't find it? He did say that he found a 3" vent in the attic that goes through the roof, and all of the 1.5" pipes he found were tied into this main vent that exhausts through the roof.

The other thing I'm wondering is whether or not a laundry room needs to be vented. It has a washer, dryer, and sink. The plumber could only find 1.5" vents coming up from the two bathrooms and the kitchen sink, but nothing coming from the laundry room. Maybe the vent is hidden in the walls and attic insulation.

Thanks for your answers so far, I appreciate your help.

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Indiana uses the IPC. Under the IPC a single 1-1/2 vent can vent up to two bath groups. Ther is no longer a requirement for a 3" vent stack off the main. Your home undoubtedly meets code and your plumber needs to go to a code update class.

This must mean YOU saw the actual piping and thus know that EVERY vent is installed properly. With the IPC he would almost have to go to classes monthly to keep up with the revisions as contractors find new ways to save money on installations. Eventually, they may reach the level of the "general contractor's code" developed years ago with 3/4" vents and vents out the side walls.

This must mean YOU saw the actual piping and thus know that EVERY vent is installed properly. With the IPC he would almost have to go to classes monthly to keep up with the revisions as contractors find new ways to save money on installations. Eventually, they may reach the level of the "general contractor's code" developed years ago with 3/4" vents and vents out the side walls.

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I did not see it BUT by his descriptions, the VALID permit and INSPECTION I would be pretty confident that it meets CODE. I had reservations about the IPC too but after studying the physics I have come to realize that venting and supply requirements have and should change with new materials, methods and low flow fixtures. There is absolutely no need whatsoever to require a full sized vent, from main through the roof. Neither is there any need to run a 2" vent on a water closet.

This must mean YOU saw the actual piping and thus know that EVERY vent is installed properly. With the IPC he would almost have to go to classes monthly to keep up with the revisions as contractors find new ways to save money on installations. Eventually, they may reach the level of the "general contractor's code" developed years ago with 3/4" vents and vents out the side walls.

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When I was working at McDonald Miller in Seattle, they plumbed a hotel in Bellevue using a type of breather fitting inside the walls in place of venting. When I stayed there, I could hear the tub drain trying to siphon the entire night I was there evertime plumbing above me was used. It saved MM a bunch of money though.

Swired,
In your case, since the home was inspected, you should be good to go. I have not installed for IPC, but it's been working for those on the East Coast.

Before I got my plumber's inspection report I never thought very much about venting. I figured you just ran a pipe out the roof and that was it. I'm surprised at how many details there are to consider and how many different ways there are to do it.

Based on everything I've heard here, and what the builder said, I'm going to assume the plumbing meets code and will be okay.

My last question is, after I move in to the house, how will I be able to tell if the plumbing vents aren't working properly? I know that smell/odor is one way, but are there any other ways?

Do you think snow should play a factor in the size of the vent through the roof? I think you get plenty of snow in Maine.

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IPC requires a minimum of one vent, 1/2 the size of the building drain through the roof but, northern climate amendments require that vent to be increased to 3" diameter, 18" below the roof and extend a minimum of 12" above the roof. Further north the diameter goes to 4" and 18" above the roof.

quote; BUT by his descriptions, the VALID permit and INSPECTION I would be pretty confident that it meets CODE.

REeally?There is a posting on a different site, with photos, of a system that I, or any other plumber, would NOT pass. (Floor drain "S" trap, multiple horizontal sanitary tees in horizontal lines, 1/16 bends changing the direction back and forth. The only real cure would be to cut it out and start over.) The inspector's only comment was that a line has excessive slope, even though the "too much slope myth" has been debunked many times in laboratories.